Applicators for delivering materials into a body cavity typically comprise a tubular insertion member having an insertion end and a gripper end opposite thereof, and an elongate expulsion member slideably fitted within the tubular insertion member for expelling the contained materials. The gripper end will generally incorporate features to allow a user to more or less securely hold the applicator during use, which includes the following steps: inserting the applicator into a body cavity, expelling a substantially enclosed material contained by the applicator, and withdrawing the applicator from the body.
Over the years, attempts have been made to improve the gripping features. One approach is to significantly reduce the diameter of the applicator in the gripper end, as can be seen in the following U.S. Pat. Nos.: 4,508,531; 4,573,963; 4,755,164; and 4,573,964. For example, Whitehead (U.S. Pat. No. 4,508,531) discloses providing a blank with a plurality of slightly recessed areas outlined by scored lines, which result in a reduced diameter gripping portion when the blank is formed into a tubular structure. Whitehead discloses that the reduced diameter is for positioning and gripping a tube prior to insertion. While a reduced diameter grip may help in preventing fingers from slipping during insertion, there is little or no resistance offered in the opposite direction during the expulsion step. This is a step with which many users have difficulty.
Another approach to improve the grip of the applicator during use is to incorporate projections, such as in the form of a ring, at the base of the applicator member being inserted into the body. Examples of this approach are disclosed in Voss, U.S. Pat. No. 4,361,150, and Sartinoranont, U.S. Pat. No. 4,447,222. Similar to the disadvantage of applicators employing a reduced diameter in the gripper end, projections typically provide only a single direction of resistance. In most cases, the resistance provided is intended to aid during the expulsion step.
A number of attempts have been made to provide dual direction resistance to finger slip. Suzuki et al., U.S. Pat. No. 4,921,474, discloses a plastic applicator having a shoulder and an annular rib spaced therefrom in a region adjacent its rear end for gripping the applicator. The drawings in '474 depict the annular rib having a smaller height dimension than that of the shoulder, resulting in decreased resistance to finger slip during a step of expelling a tampon. Forces required to expel materials from an applicator can be as great, or greater, than the forces required to place the insertion member into a body cavity, thereby necessitating the need for as great of resistance for the fingers in directions away from the insertion end as that towards the insertion end. Additionally, it is relatively easy to employ gripping features in a plastic applicator due to the inherent formability of thermoplastic materials.
Most paperboard applicators have gripping features that provide limited resistance to finger slip during use. One example of this, Hagerty, U.S. Pat. No. 5,709,652, discloses an applicator having a plurality of finger-accepting apertures to provide relatively abrupt, finger-accepting edges to frictionally resist movement of a user's finger in response to longitudinal forces on the device. Although a useful contribution to the art, the finger-accepting edges of Hagerty are limited to the wall thickness of the tubular element. The width of the finger-accepting apertures is also limiting, in that only a portion of a user's finger will fit between the edges.
Another example, Tarr et al., U.S. Pat. No. 5,330,421, discloses a tampon applicator having relatively shallow indentations at the distal end. In addition to the indentations being shallow, they are depicted as being relatively narrow, resulting in the potential of bridging the indentation with a finger. If bridging occurs, then little or no resistance is offered by the indentations.
Thus, a need still exists for a paperboard applicator having gripping features that provide significant resistance to finger slip in two directions, as needed during insertion of the applicator into a body cavity and expulsion of materials substantially contained by the applicator.